[11.19] Keck LWS Mid-IR Observations of Nearby LLAGN

B. Grossan (Instutue d'Astrophysque Spatiale, Orsay, France)

We present new Keck LWS Mid-IR (MIR) imaging observations of
a sample of LLAGN. Our results show that nuclear 10 micron
fluxes of NGC4203 and NGC4736, along with three other LLGN
from previous work, correlate with X-ray flux with the same
relation as more luminous Seyferts and quasars. The nuclear
emission of our objects is clearly differentiated from that
of starburst activity on a plot of MIR vs. X-ray flux.
Because X-ray and MIR fluxes are nearly insensitive to dust
extinction, this behavior suggests the same continuum origin
for our LLAGN sample as for Seyferts.

MIR images of the nucleus of M81 show clearly extended,
elliptical structure roughly 3.5" across the long axis (~70
pc at the source), confirming earlier, lower resolution
measurements at Palomar. This structure, the relative MIR
and X-ray nuclear fluxes, the lack of stellar emission
sufficient to power the MIR flux, and a weak UV continuum,
are evidence for material within the nucleus extinguishing
an AGN which powers the MIR emission. A unified model torus
may be the origin of the extinction.

The author gratefully acknowledges the support of the
American Astronomical Society and the LBNL Institute for
Nuclear and Particle Astrophysics (INPA) for this work.